The approaches described in this section could be pursued, but are not necessarily approaches that have been previously conceived or pursued. Therefore, unless otherwise indicated herein, the approaches described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section. Furthermore, all embodiments of the invention need not solve all (or even any) of the problems brought forward in this section.
In 3GPP GSM/CPRS/EDGE wireless devices, handling of Dual Standby mode (also known as DSDS, standing for “Dual SIM Dual Standby”). With a single RF receiver and/or a single baseband processor may experience some limitations in a situation with timing conflicts between RF activities relative to each SIM. Such conflicts may result in missing blocks related to either one SIM or the other (or both in a worst case situation). Examples of blocks that may be missed include BCCH blocks for system information and/or PCH blocks for paging. Losing these blocks lead to degraded performances (increased incoming call miss rate). Other examples of blocks that may be missed include data blocks coding speech signals.
Two possible ways to handle this situation in relation to DSDS are:                Use of two RF receivers and two baseband processors. Thus, each RF receiver and each baseband processor can serve a respective one of the SIM cards. This solution has the drawback of increasing the cost associated with the dual SIM device.        Use of a single RF receiver and a single baseband processor, and handling conflicts in software. For example, in case of conflicts between blocks related to each of the SIM cards, layer 1 software (L1) may select which block will be received and decoded. A Round Robin scheme can be applied in an attempt to limit the degradation by making the selection substantially random. However, all cases of conflicts cannot be fully solved in this approach. Thus, the performance related to each SIM card will be degraded compared to single SIM card operation. Hence, this solution suffers the drawback of not being able to achieve 100% call rate in some configurations (when conflict on paging occurs and a same DRX scheme is used for both SIMs, for example). Also, when data blocks representing speech signals are missed, this solution may not provide a satisfying quality of communication.        